U.S. patent application number 16/398792 was filed with the patent office on 2019-08-22 for method and device for producing tear-off lids and tear-off lid.
The applicant listed for this patent is SOUDRONIC AG. Invention is credited to Pascal Gauch, Peter Taiana.
Application Number | 20190256248 16/398792 |
Document ID | / |
Family ID | 52736790 |
Filed Date | 2019-08-22 |
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United States Patent
Application |
20190256248 |
Kind Code |
A1 |
Gauch; Pascal ; et
al. |
August 22, 2019 |
METHOD AND DEVICE FOR PRODUCING TEAR-OFF LIDS AND TEAR-OFF LID
Abstract
A tear-off lid with a curled edge of the removal opening is
formed such that before the edge is curled, a plastics layer
provided as a band of low thickness and preferably only 0.1 mm
thickness is applied to the collar of the lid ring. In this way, a
good seal of the cut edge of the tear-off lid is produced
economically and with the possibility for production at a high
rate.
Inventors: |
Gauch; Pascal; (Berikon,
CH) ; Taiana; Peter; (Widen, CH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SOUDRONIC AG |
Bergdietikon |
|
CH |
|
|
Family ID: |
52736790 |
Appl. No.: |
16/398792 |
Filed: |
April 30, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15304904 |
Oct 18, 2016 |
|
|
|
PCT/CH2015/000042 |
Mar 16, 2015 |
|
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16398792 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B65D 2517/5056 20130101;
B65D 2517/0013 20130101; B21D 51/383 20130101; B65D 2517/5008
20130101; B21D 51/443 20130101; B21D 51/46 20130101; B65D 17/502
20130101 |
International
Class: |
B65D 17/50 20060101
B65D017/50; B21D 51/44 20060101 B21D051/44; B21D 51/46 20060101
B21D051/46; B21D 51/38 20060101 B21D051/38 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 29, 2014 |
CH |
643/14 |
Claims
1. An apparatus for producing tear-off lids to which lids on the
upper side thereof, a tear-off film is sealed onto a sealing
surface which is arranged around a removal opening of the lid,
wherein the apparatus comprises a conveying device for lid blanks,
lid rings and tear-off lids as well as processing stations which
are provided in conveying direction (A) one after another for
processing the lid blanks, lid rings and tear-off lids, wherein a
first processing station is provided as a punching station for
forming a lid ring from the lid blank, a second processing station
is provided for forming a collar of the lid ring, extending from
the lower side of the lid ring, and a third processing station is
provided which is configured for curling the collar toward the
tear-off lid upper side and outwardly, and further at least one
sealing station is provided which is configured for sealing a
tear-off film onto the sealing surface, wherein the conveying
direction between the second processing station for forming the
collar and the third processing station for curling the collar, a
further processing station is provided which is configured as a
coating station for applying a peripheral, endless plastics layer
of substantially even thickness on the inside of the collar, and in
that the third processing station is configured for curling such
that the curl comes into contact with the plastics layer.
2. The apparatus as claimed in claim 1, wherein the coating station
is configured for applying a band-shaped plastics strip which has a
substantially even thickness, particularly a thickness in the
region of 0.05 mm to 0.5 mm and particularly a thickness of
approximately 0.1 mm.
3. The apparatus as claimed in claim 1, wherein the coating station
comprises a support which is rotatably drivable by means of a drive
for a lid ring and comprises a spray nozzle which is stationary in
the coating position and is configured to apply the plastics via
the spray nozzle, which comes to lie in the coating station within
a lid ring placed on the support, in a liquid form and band-shaped
onto the rotatingly drivable lid ring.
4. The apparatus as claimed in claim 1, wherein the coating station
comprises an extruder, a heated feed line and a heated and
controllable valve, wherein the spray nozzle can be supplied with
the melted plastics by means of the valve.
5. The apparatus as claimed in claim 3, wherein the support is
displaceable horizontally relative to its rotational axis against
the force of a spring, and in that at least one roller is provided,
the rotational axis of which extends parallel to the rotational
axis of the support and the roller is arranged at least partially
coplanar with the support and extends with the outside of said
roller into the lifting region, into which lifting region, on
lifting, a lid ring comes to lie in the processing station at the
end of the lifting movement, so that the outside of the collar of a
lid ring situated on the support can be acted upon by the
roller.
6. The apparatus as claimed in claim 1, wherein said apparatus has
a horizontally movable spray nozzle which in its one end position
of the travel path (E-F) lies closer to the rotation axis and in
its other end position of the travel path lies closer to the inside
of the collar of a lid ring situated in the processing station.
7. A tear-off lid comprising a peripheral fastening section, a
sealing flange with a tear-off film sealed thereon and a
circumferential curled edge round the sealing flange which
laterally delimits the removal opening, wherein the curled edge has
a band-shaped seal made of a plastics material, in particular a
thermoplastic elastomer (TPE) which has a substantially even
thickness.
8. The tear-off lid as claimed in claim 7, wherein the thickness of
the band-shaped seal is between 0.05 mm and 0.5 mm and, in
particular, is approximately 0.1 mm.
Description
CROSS REFERENCES TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 15/304,904, filed Oct. 18, 2016, which is a National Stage
application of Inter-national Patent Application No.
PCT/CH2015/000042, filed on Mar. 16, 2015, which claims priority to
Swiss Patent Application No. 643/14, filed on Apr. 29, 2014, each
of which is incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
[0002] The invention relates to a method and apparatus for
producing tear-off lids and a tear-off lid produced according to
the method and apparatus.
BACKGROUND OF THE INVENTION
[0003] Tear-off lids are known, for example, from DE-U 298 17 592
or from DE-U 92 03 953. A production of tear-off lids according to
the prior art and known to a person skilled in the art will now be
briefly described making reference to FIGS. 1 to 6. FIG. 1 shows a
lid blank 1. Shown at the beginning of the transport route of a
known production apparatus 20 is a stack 12 which contains a
plurality of lid blanks of this type, said blanks being removed
individually and processed by various processing stations along the
transport route wherein initially lid rings are formed from the lid
blanks and the lid rings are then further processed into the
finished tear-off lid. The lid blanks are, for example, round disks
made of coated metal which is thereby protected against corrosion,
in particular coated tinplate. They have, for example, a diameter
of 11 cm. These blanks have already been pre-formed at the edge 6
thereof by a processing machine (not shown) and the shaping of the
edge 6 later serves for fastening the finished tear-off lid to a
container or a can by means of a seam joint. This is known to a
person skilled in the art and will not be described further
here.
[0004] The conveying device 22 which conveys the lid blanks, the
lid rings and the tear-off lids in the production apparatus 20
along the transport route in the direction of the arrow A from one
processing station to the next processing station is provided in
particular by two toothed belts which run in parallel and on which
receptacles for the lid blanks or lid rings are provided, as is
known to a person skilled in the art from WO 2006/017953. This also
will not be described further here. At each of the processing
stations according to the prior art, which are known to a person
skilled in the art and are shown purely schematically here, each
blank to be processed is lifted off the conveying device and is
processed by the processing station and then returned to the
conveying device. This is indicated at the processing stations with
arrows pointing up and down. At the processing stations, the drive
of the processing stations is indicated in each case under the
conveying means. This serves to raise and lower the blanks and the
lid rings and to carry out the respective processing steps.
[0005] In a stamping processing station 23, a lid ring 2 is formed
from the lid blank 1 in that a central part 30 of the blank is cut
out and disposed of as waste. In this way, the removal opening of
the tear-off lid, which in a later production step will be closed
with the tear-off film, is formed. A sealing flange 7 remains
adjacent to the removal opening 15. At the cut edge 31, the metal
material is bare and the sheet metal of the lid ring 2 is no longer
protected there by the coating. In a processing station 24, the
edge of the removal opening is pulled up to form a collar 4 and
this collar is curled in a further processing station 25 so that a
so-called "retort curl" 5 is formed. The form of the curl, or
retort curl, can vary. The curl which forms the edge of the removal
opening ensures that the user of the can is protected from the
sharp cut edge when removing the contents of the can.
[0006] The production steps described so far were carried out in a
position in which the lid blanks and lid rings were arranged with
their later upper side or with the sealing flange 7, respectively,
facing downwardly. This is also the preferred configuration in the
present invention. As mentioned, the blank or the ring is lifted
into the individual processing stations 23, 24 and 25 from the
conveying device, processed and returned again, whereupon the
conveying device carries out conveying steps which guide the lid
blank or lid ring to the next processing station. If the production
steps are carried out, as shown, with the sealing flange 7 facing
downwardly, then a turning station 26 follows, which turns the lid
rings such that during further processing, following the turning
station, the sealing flange 7 lies in a position to face upwards in
the conveying device 22 and in the processing stations.
[0007] Thereafter, the tear-off film 8 is sealed onto the sealing
flange, and this can be carried out in two steps with a pre-sealing
station 27 and a main sealing station 28. The sealing process is
also known to a person skilled in the art and will not be described
further here. Further processing stations can follow in which an
embossing of the sealing foil can take place, the tear-off flap is
positioned and a seal tightness test is carried out. This is also
known to a person skilled in the art and will not be described
further here. At the end of the known production apparatus 20,
finished tear-off lids 10 are output, their removal opening 15
being spanned by a tear-off film 8 which is sealed onto the sealing
flange 7. The edge of the removal opening 15 is formed by an
upwardly and outwardly bent-over retort curl 5. The finished
tear-off lid 10 can be fastened, by means of the fold edge 6
thereof, to a can body (which is indicated in FIG. 5 with a body
wall part 11 only) and thereby closes the can. This is achieved
during the filling operation after the can has been filled with a
filling product. The can, once filled and closed, can be opened
later in that the tear-off film is torn off from the lid ring by
means of the tear-off tab 18, so that the removal opening 15 is
opened. Tear-off lids of this type have proved to be effective.
[0008] If the container which is closed with the tear-off lid
contains a liquid, corrosive filling product, for example, salt
water, the bare cut edge 31 can corrode. Although, due to the
upward and outward curl and with the covering by the tear-off film
in the case of the tear-off lid as described with the retort curl,
a certain degree of protection is provided against the influence of
the filling product and the bare and possibly corroded cut edge is
not visible as well, but depending on the aggressiveness of the
filling product and on the storage time of the filled container,
traces of the corrosion can nevertheless become visible. In EP-A 1
153 840, it is proposed that the tear-off film is also sealed onto
the curl itself so that the cut edge is protected against the can
contents by sealing. However, it has been found that sealing both
on the sealing flange and also on the curl is barely achievable
with reliability in production at a high production rate. WO-A
02/790041 mentions incidentally that the gap arising due to the
curl can become filled with the hot seal coating of the tear-off
film, but without explaining how this could actually be achieved
during the industrial production of tear-off films. Known tear-off
films are provided with only a very thin hot seal layer and it is
not evident to a person skilled in the art how this layer could be
used for gap filling when a hot sealing process known to the
skilled person is used. The solution suggested in WO-A 02/790041
appears therefore to be unusable in practice. From EP-B 2 055 736,
it is known to provide a container with an outward curl at the
mouth of the container, so that the cut edge does not come into
contact with water. It is proposed to provide protection of the cut
edge there with a modified hot melt material which contains a
thermoplastic elastomer.
SUMMARY OF THE INVENTION
[0009] It is an object of the invention to provide a method and a
production apparatus for tear-off lids with which a tear-off lid
can be made industrially at a high rate and at low cost, also
having practically no corrosion of the cut edge, even with
corrosive filling goods.
[0010] This object is solved with the aforementioned known method
for producing tear-off lids in that before the curling of the free
end of the collar, a band-shaped strip of plastics is applied to
the inside of the collar.
[0011] By applying a band-shaped strip, the plastic material which
reliably protects the cut edge against corrosion during the
subsequent curling when forming the retort curl can be applied with
little material cost and at a high speed.
[0012] It is preferable if the band-shaped strip is applied at an
even thickness and particularly at a very low thickness, which
amounts to only 0.05 mm to 1.0 mm. It is particularly preferable if
the band-shaped strip is applied at a thickness of approximately
0.1 mm. The even thickness produces a good sealing effect during
the curling and can save material and time during the coating. In
particular, the preferred thickness range or the preferred
approximate thickness of 0.1 mm results in a good sealing effect
with a small material input and a high coating rate. It is herein
preferable that the band-shaped strip is applied by spraying of a
liquid plastics material onto the lid ring, so that the operation
can be carried out rapidly and with a high degree of evenness.
Preferably, the plastics is a plastic material liquefied by melting
and particularly a thermoplastic elastomer liquefied by melting.
This results in the desired even and thin coating. The height of
the band can amount, for example, to from one millimeter to several
millimeters and is not critical if it is ensured, during the
curling, that the curl comes into contact with the band.
[0013] Preferably, the plastics is applied onto the rotating lid
ring by a spray nozzle which is stationary during the coating. This
variant is mechanically simple and is readily manageable for the
desired accuracy. However, it is also possible to operate with a
rotating spray nozzle and a lid ring held stationary. In
particular, the desired even thickness can be achieved if, during
the spraying on, the distance between the spray nozzle and the lid
ring is kept constant. This is preferably provided by arranging the
lid ring horizontally displaceable on its support and in that the
outside of the collar of the lid ring is acted upon by at least one
roller in order to keep the spacing of the inside of the collar
from the spray nozzle constant, since the precisely and fixedly
positioned rotatable roller defines the position of the collar
relative to the spray nozzle. This enables a mechanically simple
solution which allows the precise application of the band-shaped
strip with even thickness. Solutions in which the spacing of the
spray nozzle is continuously adjusted, by means of a distance
measurement and a displacement of the spray nozzle, to the not
exactly centrally rotating lid ring are also possible, although the
claimed mechanically simpler solution is preferred.
[0014] It is a further object of the invention to provide a
production apparatus for tear-off lids, by means of which tear-off
lids can be manufactured at a high rate and economically, but which
does not have the above-mentioned disadvantage.
[0015] This object is achieved with the apparatus having the
features described hereinafter.
[0016] Through the provision of a coating station with which a
peripheral band-shaped plastics layer can be applied to the inside
of the collar of the lid rings, the protection of the curled cut
edge is enabled since the curl contacts the plastics layer which
forms a seal.
[0017] Preferably, the apparatus according to the claim is designed
such that the coating station is configured for applying a
band-shaped plastics strip which has a substantially even
thickness, particularly a thickness in the range from 0.05 mm to
0.5 mm and particularly a thickness of approximately 0.1 mm. This
embodiment provides good protection with a low material use and
very high processing speed so that the coating station can operate
at the same rate as the other processing stations of the apparatus.
It is also preferred that the coating station has a rotatably
drivable receptacle for a lid ring and a spray nozzle which is
stationary during the application of the band in order to apply the
plastics in a liquid form and band-shaped onto the rotatingly
driven lid ring by means of the spray nozzle, which comes to lie in
the coating station within a lid ring placed on the receptacle when
the lid ring has been lifted from the conveying device by the
coating station. This results, reproducibly, in the desired
plastics layer of low thickness.
[0018] Preferably, the plastics is liquefied in that the coating
station is equipped with an extruder, with a heated supply line to
a controllable valve and a heated valve, so that the spray nozzle
can be supplied by means of the valve with the melted plastics for
the application thereof under pressure. Preferably, the support or
receptacle, respectively, for the lid ring is also displaceable
horizontally relative to its rotational axis against the force of a
spring and at least one roller is provided, the rotational axis of
which extends parallel to the rotational axis of the receptacle,
wherein the roller is arranged at least partially coplanar with the
receptacle and extends into the region which, with the lid ring
lifted, is encompassed thereby. By this means, the outside of the
collar of a lid ring situated on the support can be acted upon by
the roller if the lid ring is lifted and, since the position of the
roller is precisely defined, the horizontal position of the lifted
lid ring is also precisely defined. This enables, by simple means,
the spacing of the inside of the collar of the lid ring from the
spray nozzle to be kept constant, which leads to the desired
constant thickness of the plastics coating on the inside of the
collar. In order to undertake the application of the band, the
spray nozzle is moved toward the rotating lid ring, the position of
which is defined horizontally by the roller and, following the
coating, is moved away again.
[0019] It is a further object of the invention to provide a
tear-off lid which does not have the above-mentioned disadvantages
and can be economically manufactured industrially at a high rate
and quality.
[0020] This object is achieved with the tear-off lid having the
features described hereinafter.
[0021] Preferably, the thickness of the band-shaped seal is between
0.05 mm and 0.5 mm and, in particular, is approximately 0.1 mm. The
height of the seal can be 1 mm to 3 mm.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Further embodiments, advantages and uses of the invention
are disclosed by the dependent claims and the following description
making reference to the drawings, in which:
[0023] FIGS. 1 to 5 are vertical sectional views through a lid
blank, a lid ring and a tear-off lid to illustrate processing steps
in the formation of a tear-off lid according to the prior art;
[0024] FIG. 6 is a schematic side view of an apparatus according to
the prior art for producing tear-off lids or for carrying out the
steps according to FIGS. 1 to 5;
[0025] FIG. 7 is a vertical sectional view of a lid ring during the
production of a tear-off lid according to the invention;
[0026] FIG. 8 is an enlarged view of a portion of the lid ring of
FIG. 7;
[0027] FIG. 9 is the lid ring of FIG. 7 after curling of the edge
of the removal opening;
[0028] FIG. 10 is an enlarged view of a portion of the lid ring of
FIG. 9;
[0029] FIG. 11 is a plan view of the lid ring of a tear-off lid
according to the invention;
[0030] FIG. 12 is a schematic representation of the processing
station for applying the seal;
[0031] FIG. 13 is a schematic side view of an apparatus according
to the invention for producing tear-off lids with a sealed cut
edge;
[0032] FIGS. 14 to 17 are illustrations of the positioning of the
lid ring in the processing station and the movement of the spray
nozzle in a preferred embodiment; and
[0033] FIGS. 18 to 21 are enlarged illustrations of the positioning
of the spray nozzle for the application of the plastics.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0034] In the introductory part, the production of tear-off lids
according to the prior art as known to a person skilled in the art
was described, making reference to FIGS. 1 to 6. For the avoidance
of repetition, reference is made here to this description.
[0035] The procedure according to the invention will now be
described, wherein reference is made, where necessary, to the known
apparatus and the known, production steps described above. In
particular, in the apparatus and the method according to the
invention for forming the lid ring from the lid blank and for the
sealing of the tear-off film, the procedure as already known to a
person skilled in the art is carried out.
[0036] FIGS. 7 and 8 show a lid ring wherein the processing step of
drawing the edge of the removal opening to form the collar 4 has
already taken place. This has been performed in the processing
station 24. In the preferred example according to the invention as
shown, herein (or in a separate step) an inward curvature which
facilitates the later curling to form the retort curl has been
created at the upper end 34 of the collar 4. According to the
invention, in an operation at the inside 40 of the collar 4, a
plastics layer in the form of a band 32 is applied. The application
of this plastics layer is preferably carried out in a separate
processing station 29, as shown in FIG. 13. This processing station
29 is arranged between the drawing station 24 and the curling
station 25.
[0037] During curling, the band 32 made of the plastics layer forms
a seal for the cut edge 31, as will now be described. The band 32
consists of a plastics material and is preferably made of a
thermoplastic elastomer (TPE). TPE plastics of this type are
commercially available, particularly in qualities which reliably
resist the sterilization temperature during sterilization of the
filled container, so that the seal formed by the band is retained
during the sterilization. As shown, the band is preferably formed
with uniform thickness over the whole height of the band. It is
provided as a thin band which preferably has a thickness d in the
range of 0.05 millimeters to 0.2 millimeters, and preferably a
thickness of approximately 0.1 millimeters. The height H of the
band can be, for example, 1 mm to 3 mm.
[0038] The coating according to the invention takes place by means
of the spraying-on of a melted, liquid plastics material,
preferably the aforementioned TPE, wherein a relative movement of
the nozzle and the lid ring takes place. Preferably, the lid ring
is rotatingly moved in the processing station 29 (FIGS. 12 and 13)
and the inside 40 of the collar 4 is moved past the exit opening of
a spray nozzle from which the plastics material emerges and which
nozzle is arranged to be static during the coating. Thus, the lid
ring is lifted at the processing station 29, caused to rotate and
the coating is activated when the lid ring has reached the right
position relative to the exit opening of the nozzle. Following at
least one full rotation, if a gapless peripherally extending band
is formed at the inside, the lid ring with the band 32 is again
moved downwardly to the conveying device, wherein the rotation is
ended so that the lid ring can again be placed on the receptacles
of the conveying device. Then follows the conveying to the curling
station 25. The plastics material of the band 32 already starts to
cool down during the coating onto the lid ring and solidifies so
that during further conveying, no flowing of the plastics takes
place and the band is stable in the form shown. If necessary, in
the coating station or the processing station 29, a cooling means,
e.g. in the form of a blower can be provided.
[0039] The lid ring can be rotated at a high speed during the
coating of the thin plastics band, wherein this should be
understood to include a rotation of more than 200 rotations per
minute. A preferred rotational speed lies in the range of 400 per
minute to 600 per minute.
[0040] During the coating, it is ensured that the spacing of the
application opening or of the spray nozzle from the inside 40 of
the collar 4 during spraying on of the liquid plastics remains
substantially constant so that the thickness of the band 32 is
substantially constant and the low thickness thereof is possible.
This can be achieved, for example, in that the lid ring 2 is
precisely centered in the processing station 29 on a receptacle and
the spray nozzle with the application opening has a defined spacing
relative to this receptacle. However, the transfer from the
conveying means with subsequent centering requires time so that,
for the very high production rates striven for, the procedure
followed is preferably such that the lid ring is pressed in the
processing station with the outside of the collar 4 against a
roller which is precisely positioned relative to the injection
nozzle position during the coating, so that the spacing of the
spray nozzle from the inside 40 of the collar 4 is precisely
defined by simple means. This will now be described in greater
detail making reference to FIG. 9 and FIGS. 14 to 17 and 18 to
21.
[0041] It is evident that the band 32 is positioned at the inside
40 of the collar 4 such that it lies closer to the plane of the
sealing flange 7 than to the cut edge 31. The positioning and
dimensioning of the band is approximately such that the band 32
covers the lower third of the collar 4 to the lower half of the
collar 4. It is possible for the band to have a greater height H,
although the material cost for the plastics used then increases,
but this is not necessary for the further processing or for
protection of the cut edge. In practice, the height H of the seal
can be approximately 1 mm to 3 mm.
[0042] The lid ring provided with the plastics band according to
FIGS. 7 and 8 is provided in known manner in the processing station
25 with a retort curl 5. This station 25 operates according to the
prior art with the known curling tools, so that this need not be
described in detail here, being known to a person skilled in the
art. A modification which is obvious to a person skilled in the art
is possibly present in the tools if the collar 4 has already been
bent forward at its upper edge 34 for the curling, which is
preferable. It is evident, according to FIGS. 10 to 13 which show
the lid ring after the turning station 26 and particularly
considering FIG. 12, that during the formation of the retort curl
5, the band 32 forms a seal which prevents the entry of liquid to
the interior of the retort curl. Thus the bare cut edge 31 is
protected against the influence of a liquid present in the can. It
is unimportant whether the curling takes place in such a way that
the cut edge 31 is partially embedded in the band 32, as shown or
whether it only lies against the band 32. Also the opposite, that
the cut edge 31 cuts through the band 32 and lies against the metal
of the inside 40 does not disturb the function of the band 32.
Thus, the normal production tolerances in the formation of the
retort curl 5 play no part. The plan view 12 shows the lid ring as
it is transported into the sealing station 27 in which the tear-off
film is sealed on over the removal opening.
[0043] FIG. 13 shows the production apparatus 20 for the tear-off
lid, in which a processing station 29 is provided for the coating
of the band 32 on the lid ring. The processing station 29 is
preferably configured according to FIG. 12 and FIGS. 14 to 21.
[0044] FIG. 12 shows a support 50 which is adapted, in its diameter
and form, to the lid rings 2. A lid ring 2 lies with its sealing
flange 7 against the upper side of the support 50. The support 50
can be moved up and down in a known manner as with the other
processing stations, so that the support can be moved downwardly in
the direction of the arrow C in the drawing, by which means the
support is lowered beneath the receptacles for the lid ring of the
conveying device 22, such that the lid ring is again passed to the
conveying device so that it can be transported to the next
processing station 25. On the other hand, the next lid ring which
is to be received into the processing station 29 is taken up by the
receptacle 50 or is lifted off the conveying device when the
receptacle 50 is moved upwardly again in the direction of the arrow
B. This is fundamentally known to a person skilled in the art in a
similar manner from the other processing stations and the drive for
moving the support 50 up and down is shown only schematically as a
box 58. This drive can be configured in known manner electrically
and/or pneumatically.
[0045] In the preferred processing station 29, the support 50 is
displaceable resiliently in the horizontal direction of the arrow
E-F relative to the vertical central axis 55. This can be carried
out in various ways and in the present example is solved in that a
central conical holder 52 is provided which lies fixed in the
position of the central axis 55 (but is rotatable thereabout, as
will be explained below) and in that elastic spring means, for
example, in the form of a peripheral plastics hose 54 is provided
which enables the support 50 to move in the direction of the double
arrow E-F by a few tenths of a millimeter to millimeters
horizontally or perpendicularly to the central axis 55,
respectively. In this way, the lid ring can also be displaced by
this amount in the direction of the double arrow. The spray nozzle
46 which sprays the plastics material to form the band 32 against
the inside 40 of the collar 4 of the lid ring 2, however, is
arranged fixed in its coating position (but displaceable into the
coating position, as will be described below). The spacing of the
spray nozzle 46 from the inside 40 is kept constant during the
application of the plastics material in that a roller 45 which is
rotatable about a vertical rotary axis is arranged adjoining the
support 50. The position of the rotary axis 47 in the processing
station 29 is fixed and is defined relative to the spray nozzle in
the application position thereof, such that the plastics coating is
carried out at a defined thickness.
[0046] The displacement drive 48 by means of which the spray nozzle
46 is displaceable in the direction of the double arrow E-F is
shown as a box and is, for example, configured as an electric motor
or as electromagnetic or pneumatic. This displacement of the spray
nozzle is shown more exactly on the basis of FIGS. 14 to 21.
[0047] When the support 50 is raised, the lid ring 2 is positioned
centrally to the axis 55 by the spring means 54. The spray nozzle
46 has been positioned by its drive 48 displaced toward the axis 55
or in the direction E, as shown in FIGS. 14 and 15 and FIGS. 18 and
19. In this position, on lifting in the direction of the arrow B,
the spray nozzle will enter into the lid ring 2. For the preferred
inwardly facing curvature of the edge 34 of the collar 4 also,
there is sufficient space and the spray nozzle is not a hindrance
in this moved back position for the lifting movement of a lid ring
of this type. The lid ring 2 or the support 50 and holder 52 of the
support is brought into rotation about the axis 55 by the drive 58,
for example, at the above-mentioned rotary speed of 600 per minute.
At the end of the lifting movement of the lid ring 2, the lid ring
makes contact with the outside of its collar 4 against the outside
of the roller 45, since the roller 45 is arranged in the processing
station such that it extends into the region encompassed by the
raised lid ring. The FIGS. 14 and 18 show the position during
lifting shortly before the collar 4 touches the roller 45. The
FIGS. 15 and 19 show the position in which the lifting movement is
completed and the collar 4 lies against the roller 45. Since the
position of the roller 45 in the processing station 29 is precisely
defined in the horizontal direction, the position of the collar 4
where it touches the roller 45 is also precisely defined. Thanks to
the spring means 54, the lid ring can be adjusted in the horizontal
position such that the lid ring assumes the position of the roller
45. However, the roller 45 is rotatable but not driven itself since
it takes on the rotation of the lid rings.
[0048] Once the lifting is ended and once the lid ring has thus
reached the position shown in FIGS. 12, 15 and 19, the spray nozzle
46 is moved by its drive 48 in the direction F and assumes its
fixed application position. Since the position of the roller 45 in
the processing station has been precisely defined in its distance
from the spray nozzle, the inside 40 of the collar 4 is also
positioned at a precise spacing relative to the spray nozzle for
the spraying-on of the plastics material onto the inside 40, when
the spray nozzle 46 has reached its end position in the direction
F, as shown in FIGS. 16 and 20. The recess 49 in the spray nozzle
46 enables the approach of the spray nozzle 46 to the collar 4
despite the curvature of the collar at the end 34. Once the spray
nozzle 46 has reached its end position, the spraying-on is started
and takes place throughout a complete rotation (or, if required, a
plurality of full rotations) of the lid ring. FIGS. 12, 17 and 21
show the spraying-on by the spray nozzle. In this way, the band 32
of plastics is made in a precisely selectable thickness. The height
H of the band 32 depends on the selection of the spray nozzle. The
spraying-on of the plastics is stopped and the spray nozzle 46 is
moved back by its drive 48 in the direction of the arrow E.
Furthermore, the rotation of the support 50 and the holder 52 is
ended and the support 50 is moved downwardly in the direction of
the arrow C, wherein the lid ring loses contact with the roller 45
again. The lid ring 2 equipped with the band 32 is again laid on
the conveying means and the next conveying step takes place and
conveys the lid ring equipped with the plastics band 32 to the next
processing station 25.
[0049] The supply of liquid melted TPE plastics to the spray nozzle
46 can take place in a fundamentally known manner in that the
plastics is melted in an extruder 60 and is extruded and, for
example, is fed through a heated hose line 61 in liquid form and
under pressure to the processing station. This is indicated purely
schematically with lines so that the actual embodiment of the entry
of the line into the head containing the spray nozzle is not shown.
A controllably openable and closable valve 62 which is also
preferably heated, causes the start and the end of the spraying of
the plastics. A control system 63 can control the outlined sequence
of the lifting from the conveying means, the rotation of the
support with the lid ring about the axis 55 and the displacement of
the spray nozzle 46 and the start of spraying and the ending of
spraying and the withdrawal of the spray nozzle, the ending of the
rotation and the lowering of the support. This control system can
be a control unit provided at the processing station 29 or is a
joint control unit common to a plurality of, or all, the processing
stations and the conveying means 22.
[0050] The aforementioned FIGS. 14 to 17 show an example of the
drive 48 of the spray nozzle 46 in more detail. This is movable
horizontally in a linear guide in the direction E-F, which is
brought about here by means of an eccentric drive. In FIGS. 18 to
21, the positioning of the spray nozzle relative to the inside of
the collar 4 is shown enlarged. The channel for the plastics in the
interior of the spray nozzle 46 is also shown with dashed lines.
The displacement of the support 50 and thus of the lid ring 2 on
contact of the lid ring with the outside of the roller 45 is
indicated in FIG. 19 with the arrows G.
[0051] Whilst in the present application, preferred embodiments of
the invention are described, it should be made clear that the
invention is not restricted thereto and can also be carried out in
other ways within the scope of the following claims.
* * * * *